> No component in a complex system should depend on the internal details of any other component. Unfortunately, the internal details of other components are im

> No component in a complex system should depend on the internal details of any other component. Unfortunately, the internal details of other components are important for performance. It is not enough to know that something is e.g. an ordered collection; I also need to know whether accessing items randomly has an O(1) or O(n) cost. Increasing the complexity from linear to quadratic is not a minor detail that a faster processor would solve. But when you start caring about performance, suddenly you don't deal with ordered collections, but with arrays, linked lists, red-black trees, and whatever. Then you also get unspecified ordered collections returned from other modules, and you wonder whether it is okay to use them as they are, or whether you should pay a one-time price to convert them to a more efficient collection. And somewhere, a new programmer is crying: "I just wanted to create a list containing dozen numbers, why do I have to deal with all this complexity?"